Strange geometry when creating a face from points
I suppose you've given a Subdivision Surface modifier to your objects.

Subdivision Surface divides each edge with a new vertex, then join these new vertices in order to divide each face.

Here you have only one face, so all the new vertices will join at the center of this face. But giving your geometry this will happen out of the shape and this will give outer faces.

To avoid that you need to create some inner edges, like that: